Facet joints have been described as an important source of low back pain. The value of medial branch blocks in the diagnosis of facet joint mediated pain is considered important. However, the therapeutic value of medial branch blocks has not been determined. This study was designed to evaluate the duration of relief obtained and therapeutic value following controlled medial branch blocks with or without adjuvant agents Sarapin (High Chemical Company, Levittown, PA) and Depo-medrol (Pharmacia and Upjohn Company, Kalamazoo, MI). The study population consisted of 180 consecutive patients seen in a single pain management practice, divided into three groups with 60 patients in each group. Group I was treated with local anesthetic only, Group II with the addition of Sarapin, and Group III with the addition of Depo-medrol along with Sarapin. The prevalence of facet joint pain in chronic low back pain was determined as 36%, with a false-positive rate of 25%. Comparison of duration of relief in days with each block in the three groups showed that the relief was significantly superior in Group III compared with Group I and Group II, whereas Group II was superior to Group I.